US 2515747 A
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Description (OCR text may contain errors)
July 18, 1950 D. J. VAUGHAN 2,515,747
LAMP BASE Filed Nov. 14, 1949 IT'NQITEOVI Daniel, J. Vaughan, b Wale Hi5 A bkorneg.
Patented July 18, 1950 2,515,147 LAMP BASE Daniel J. Vaughan, Euclid, Ohio, asslgnor to General Electric Company, a corporation of New York Application November 14, 1949, Serial No. 127,171
2 Claims. 1
My invention relates to lamp bases for electric lamps and similar devices and more particularly to electric lamps having elongated envelopes with bases at both ends which engage suitably spaced sockets.
In the U. 8. Patent 2,338,835, issued January 11, 1945, to F2. D. Bryant and assigned to the assignee of the present application, a supporting base for such lamps is disclosed and claimed as well as a socket for receiving the lamp base. The base described in the patent comprises an electrical contact-carrying body portion of insulating material, preferably porcelain, to which is secured a metal skirt for attaching the base to the elongated tubular glass or quartz envelope of the lamp. While bases of the type described in the patent have been successfully used for many years, they have not been entirely satisfactory due to the difliculty in providing a tight connection between the metal collar or skirt and the porcelain insulator forming the main body of the base.
Obviously, a tight connection between these parts is highly desirable in order to obtain proper mounting of the lamp in lighting fixtures and the like; and it is the principal object of the present invention to provide a strong, firm, tight connection between these base elements. Further objects and advantages attaching to the invention will be apparent from the following detailed description and from the accompanying drawing in which Fig. l is a perspective view of a lamp base embodying my invention and Fig. 2 is a partly sectional view of the base along the line 2-2 of Fig. 1 and showing one end of a lamp in full.
Referring to the drawing, the base I is mounted on an elongated tubular glass or quartz lamp envelope 2 which may contain an electrode in each end where the device is a discharge lamp or, in the case of an incandescent lamp. a filament extending longitudinally from end to end of the envelope. The base I comprises a body portion 3 of insulating material, preferably porcelain. The said body portion 3 is secured to the end of the envelope 2 by means of a metal skirt or collar 4 which is secured to an enlarged shoulder 5 on said body portion 3. Before the skirt 4 is slipped over the end of the tube 2, a thin strip 6 of asbestos paper moistened with a. solution of sodium silicate is wrapped around the envelope 2. The skirt 4 is secured firmly in place on the envelope 2 by a suitable clamping strip 'i, the skirt 4 being provided with a multiplicity of slits 8 therein so as to be readily compressible by clamping strip 1 around the asbestos strip 6 and clamp the latter between the lamp envelope 2 and the clamp I. The outer end 9 oi the body portion 8 carries a spade-shaped nietal electrical contact prong it which extends outwardly therefrom and longitudinally of the lamp envelope 2. The said prong i0 is electrically connected by a flexible conductor ii to the end of a current lead-in wire I! which extends through a seal l3 and is electrically connected to the electrode or filament (not shown) in the envelope 2. The conductor it extends through a longitudinal opening in the prong l0 and is soldered to the prong at its outer end.
The physical connection between the body-portion 3 and the skirt 4 of the base of the present invention is different than the connection be tween these components of the patented base in which the skirt is provided with an annulardepression, or bead, spaced inwardly longitudinally from the end of the skirt opposite the slit end thereof, the shoulder of the body portion is inserted in the said solid wall end of the skirt and held against the bead and the said solid wall end portion of the skirt is crimped over the shoulder to clamp the shoulder in the skirt. Due to the difficulty of making porcelain bodies to close tolerances, the physical connection be-v tween the skirt and the porcelain body portion of the patented base was frequently loose and therefore not entirely satisfactory.
In accordance with the present invention, the skirt 4 is tightly secured to the body portion 3 by' a split metal snap ring I4 inside the skirt 4 which ring 14 is forced against the side ii of the shoulder 5 of the body portion 3 and held in such position thereagainst by the four indentations or dimples l6 spaced apart in the wall of the skirt 4. The bottom wall ll of the skirt 4 is partially closed by an inwardly extending flange l1 and coincides in form with and engages the side 18 of the shoulder 5 of the portion 3.
In assemblin the base I, the body portion 3 is passed through the end of larger diameter of the skirt 4 until the flange ll of the partially closed bottom wall I! of the skirt 4 engages the side l8 of the shoulder ii of the body portion 3. The snap ring i4 is then placed and held in position against the side l5 of the shoulder 5 of the body portion 3 and the four dimples it are then punched in the wall of the skirt 4 to hold the ring l4 against the side ii of the shoulder 5. The snap ring l4 serves as a cushion against the shock of mechanical press assembly and, when held in position by the dimples it, maintains a pressure against the dimples l6 and against the shoulder 5 of the portion 3 suflicient to provide the desired tight physical connection between the skirt 4 and the body portion 3.
This structure and the method of assembling the base I permits rather large tolerances in the dimensions of the porcelain body portion 3 of the base 'I, such porcelain bodies being difiicult to make to close tolerances. The snap ring l4 compensates for any variation in the size or the body portion 3 within a reasonable range of size variation.
Relative rotary displacements between the body portion 3 and the skirt 4 are prevented by four depressed longitudinal slots l9 spaced 90 apart in the shoulder 5 oi! the body portion 3 of the base I into which fit inwardly and-longitudinally extending ridges 20 in the wall ll of skirt 4. The dimples I6 are spaced from the ridges 20 an angular distance of 45, preferably. The slits 8 are made in the skirt 4 preferably after the skirt 4 and the body portion 3 have been secured together as described above.
What I claim as new and desire to secure by Letters Patent 01 the United States is:
l. A base for a double-ended electric lamp comprising a hollow tubular body portion of electrically insulating material adapted to carry at one end an electrical contact and having a shoulder at its opposite end and a metal skirt overlapping and secured to said shoulder by an integral inward flange engaging one side of said shoulder and a split snap ring of metal held against the other side of said shoulder by radially spaced indentations in the wall of said skirt.
2. A base for a double-ended electric lamp comprising a hollow tubular body portion of electricalLV insulating material adapted to carry at one end an electrical contact and having a shoulder at its opposite end and a metal skirt overlapping and secured to said shoulder by an integral inward flange engaging one side '01 said shoulder and a split snap ring of metal held against the other side of said shoulder by radially spaced indentation in the wall of said skirt to hold said body portion and said skirt tightly together, said shoulder having longitudinally extending slots in its periphery and said skirt having longitudinally extending indentations fitting into said slots to hold said elements against relative rotary displacements.
DANIEL J. VAUGHAN.
No references cited.